Objective: To evaluate the prevalence of undiagnosed rheumatic diseases in the first trimester of pregnancy.
Design: We screened for rheumatic diseases in 1210 consecutive pregnant women during the first trimester of pregnancy using a 10-item questionnaire.
Setting: A university hospital in northern Italy.
Population: One hundred and thirty-seven (11.3%) women who answered positively to at least one question constituted the cases and were compared with 107 negative controls.
Methods: Cases and controls were tested for rheumatic autoantibodies (antinuclear antibody, anti-double-stranded DNA, anti-extractable nuclear antigen, anticardiolipin antibody, anti-beta2-glycoprotein I antibodies and lupus anticoagulant) and were evaluated by a rheumatologist for a definite diagnosis of rheumatic disease.
Main outcome measures: Prevalence of undiagnosed rheumatic disease in the first trimester of pregnancy.
Results: The overall rate of positivity to the antibodies tested was 43.1% (59/137) among cases and 9.3% (10/107) in the controls (P < 0.001). A definitive diagnosis of rheumatic disease was made in 35 cases (25.5%) and in none of the controls (P <0.001). In stepwise logistic regression analysis, photosensitivity (adjusted OR 5.72; 95% CI 2.38-13.8), erythema or malar rash (adjusted OR 3.91; 95% CI 1.53-10) and history of two or more miscarriages (adjusted OR 5.6; 95% CI 1.55-20.6) were independent predictors of a definitive diagnosis of rheumatic disease (area under receiving operator curve = 0.814; 95% CI 0.76-0.86). Birthweight was lower (3180 g +/- 475 compared with 3340 g +/- 452, P= 0.008), and overall serious pregnancy complications (miscarriage, fetal growth restriction, delivery before 34 weeks of pregnancy and severe pre-eclampsia) were higher among cases (12/137) than controls (2/107) (adjusted OR 5.60; 95% CI 1.29-24.3; P= 0.021).
Conclusions: A two-step screening process with a self-administered questionnaire proved to be a useful method to screen for undiagnosed rheumatic diseases during the first trimester of pregnancy.